I think the technologies developed to make a mars habitat possible we end up also being useful for making some parts of a future earth habitable. That's a coincidence I hope doesn't come true.

Personally, I think every billion destined for mars exploration is money not being spend on addressing the more pressing crisis: What about the health of our current planet. Mars can wait, so to speak, for us to ensure our survival here on earth. A mars colony probably wouldn't survive a collapse of earth-based civilization.

> How can the same people be worried about human extinction as a result of environmental collapse, also think we might be able to develop a sustainable colony on Mars.

We would control the size and direction of growth on a colony. As it stands the tradoffs we make with regard to earth's climate affect 7.5+Bn people. A colony can be planned/optimized before we get there. We don't need to terraform the entirety of mars to get a small colony. If you want to have mars rival earth, then we can start talking about the scales of comparison you're making.

You're quite right. Let's see some habitable biodomes out in the Sahara, a much more tractable environment than Mars. But nobody seems to be pursuing this technology at scale, preferring to focus on the rockets.

Agreed. I suggest all scientists/engineers working on Mars or Lunar habitability, office exclusively in Antarctica.... once they get their offices up and running and self-sustaining, I'll pay more attention to them.

I don't believe we will be able to develop a sustainable colony on Mars, at least not with present technology. Every attempt we have made to build a self-sustaining ecosystem, such as Biosphere 2, has failed.

Eerily when Biosphere 2 collapsed the insects died first, which is exactly what we are observing now globally.

Unrelated: But Biosphere 2 has a nice Facebook page, and they are worth following for their live events.

https://www.facebook.com/pg/Biosphere2/

I love seeing experiments with vertical farming.